The possibility of a failure of the aircraft's engine or systems was discarded because examination of the aircraft did not reveal any irregularity and no distress call was received from the pilot. There is no evidence that there was an emergency, or that the aircraft presented problems before impact. On take-off from Lac Portneuf, the prevailing weather conditions at the points of departure and arrival were favourable for visual flight. The pilot could not have known that local conditions along the way were poor, as the area is largely uninhabited and weather information was not available. The pilot, who was unfamiliar with the area, planned to fly at a cruising altitude of 2,500 feet asl whereas the ceiling at Lac Sbastien was 2,000 feet asl. The chosen route was over mountainous terrain, with some mountain peaks concealed by the clouds; consequently, the pilot was unable to recognize the dangers that he was likely to encounter. He would have found himself in reduced visibility conditions in which he lost sight of the ground and would no longer have the visual references necessary to avoid collision with obstacles. Faced with deteriorating weather conditions, which made continuation of the flight hazardous, the pilot had to make a decision either to find a suitable lake for landing or to make a diversion. The pilot decided not to land, but to deviate from the direct route and try to reach his destination by veering southeast in order to fly in visual meteorological conditions (VMC); he may have even tried to follow the power transmission line. It is likely that the pilot was not aware of his true position in relation to the terrain and topography of the area and was relying on the GPS to get to his destination because the weather conditions required him to focus the greatest part of his attention on manoeuvring the aircraft to maintain VMC. In low-altitude flight, his field of view had to be very limited, and, because navigation charts are planform views whereas nothing is seen in planform at this height, the pilot would have difficulty in following the progress of the flight on the VFR navigation chart on which the elevation of the terrain appeared. Consequently, although the pilot knew where Lac Sbastien was located in relation to his aircraft, he did not know his exact position and was flying at an altitude lower than some of the surrounding terrain. The aircraft's attitude on impact suggests that the pilot was controlling the aircraft just prior to the accident. It is therefore conceivable that the pilot probably did not have the necessary visual references and did not see the ground in time to avoid it. Why the pilot decided to continue the flight in adverse conditions could not be determined. It is likely that the nearness of the destination, and the pilot's reliance on the GPS, had an influence on his decision. As the return journey had already been delayed by one day because of adverse weather conditions, it is also possible that the desire of the pilot and the passengers to return home influenced the pilot's decision to undertake the flight.Analysis The possibility of a failure of the aircraft's engine or systems was discarded because examination of the aircraft did not reveal any irregularity and no distress call was received from the pilot. There is no evidence that there was an emergency, or that the aircraft presented problems before impact. On take-off from Lac Portneuf, the prevailing weather conditions at the points of departure and arrival were favourable for visual flight. The pilot could not have known that local conditions along the way were poor, as the area is largely uninhabited and weather information was not available. The pilot, who was unfamiliar with the area, planned to fly at a cruising altitude of 2,500 feet asl whereas the ceiling at Lac Sbastien was 2,000 feet asl. The chosen route was over mountainous terrain, with some mountain peaks concealed by the clouds; consequently, the pilot was unable to recognize the dangers that he was likely to encounter. He would have found himself in reduced visibility conditions in which he lost sight of the ground and would no longer have the visual references necessary to avoid collision with obstacles. Faced with deteriorating weather conditions, which made continuation of the flight hazardous, the pilot had to make a decision either to find a suitable lake for landing or to make a diversion. The pilot decided not to land, but to deviate from the direct route and try to reach his destination by veering southeast in order to fly in visual meteorological conditions (VMC); he may have even tried to follow the power transmission line. It is likely that the pilot was not aware of his true position in relation to the terrain and topography of the area and was relying on the GPS to get to his destination because the weather conditions required him to focus the greatest part of his attention on manoeuvring the aircraft to maintain VMC. In low-altitude flight, his field of view had to be very limited, and, because navigation charts are planform views whereas nothing is seen in planform at this height, the pilot would have difficulty in following the progress of the flight on the VFR navigation chart on which the elevation of the terrain appeared. Consequently, although the pilot knew where Lac Sbastien was located in relation to his aircraft, he did not know his exact position and was flying at an altitude lower than some of the surrounding terrain. The aircraft's attitude on impact suggests that the pilot was controlling the aircraft just prior to the accident. It is therefore conceivable that the pilot probably did not have the necessary visual references and did not see the ground in time to avoid it. Why the pilot decided to continue the flight in adverse conditions could not be determined. It is likely that the nearness of the destination, and the pilot's reliance on the GPS, had an influence on his decision. As the return journey had already been delayed by one day because of adverse weather conditions, it is also possible that the desire of the pilot and the passengers to return home influenced the pilot's decision to undertake the flight. The pilot was certified and qualified for the flight in accordance with existing regulations and there is no evidence that incapacitation or physiological factors affected the pilot's performance. There was no evidence found of any airframe failure or system malfunction prior to or during the flight. The chosen route was over terrain whose high points were higher than the cloud ceiling and the pilot did not know the weather conditions along the route. The pilot decided not to land, but continued pressing toward his destination. In an attempt to remain VFR, the pilot probably relied on the GPS to navigate rather than map read when the weather conditions deteriorated. In the moments preceding impact, the pilot probably did not have the necessary visual references to avoid striking the mountain.Findings The pilot was certified and qualified for the flight in accordance with existing regulations and there is no evidence that incapacitation or physiological factors affected the pilot's performance. There was no evidence found of any airframe failure or system malfunction prior to or during the flight. The chosen route was over terrain whose high points were higher than the cloud ceiling and the pilot did not know the weather conditions along the route. The pilot decided not to land, but continued pressing toward his destination. In an attempt to remain VFR, the pilot probably relied on the GPS to navigate rather than map read when the weather conditions deteriorated. In the moments preceding impact, the pilot probably did not have the necessary visual references to avoid striking the mountain. The pilot continued his flight in adverse weather conditions and probably did not have the necessary visual references to avoid hitting the steep slope of the mountain. Likely contributing to this occurrence was the pilot's reliance on GPS and not the navigation chart while attempting to maintain VMC.Causes and Contributing Factors The pilot continued his flight in adverse weather conditions and probably did not have the necessary visual references to avoid hitting the steep slope of the mountain. Likely contributing to this occurrence was the pilot's reliance on GPS and not the navigation chart while attempting to maintain VMC.